An Inexpensive Kinetic Study: The Reaction of FD&C Red #3 (Erythrosin B) with Hypochlorite

Abstract

Kinetics constitutes a core topic in both the lecture and laboratory components of lower- level chemistry courses. While textbook examples can ignore issues of time, temperature and safety, the laboratory can not. Reactions must occur slowly enough to be detected by students, occur rapidly enough for data collection in the few hours assigned to a laboratory period, be safe enough to be handled by students, and be simple enough to provide easily interpreted data. Few reactions meet these restrictions. We report here a new, inexpensive (~5 cents/student), environmentally benign system involving the reaction of FDandC Red #3 and hypochlorite. Students use a desktop visible spectrophotometer to quantitatively follow the rate of disappearance of the colored reagent under a variety of initial conditions. The first-order reaction in both dye and bleach yields simple data that students can easily process and graph using spreadsheet software to obtain the rate constant and the rate law.

A homogeneous chemical reactor analysis and design laboratory: The reaction kinetics of dye and bleach

“…The reaction of chemical dyes with commercial bleach to form colorless products (neutralizing or altering the dye's normal color) involves common household materials without any exceptional restrictions on handling or disposal. The fact that the reaction may occur visibly in an aqueous solution for a variety of dyes and food colorings has made it a very popular example for the instructors of chemistry and chemical engineering (Pickering and Heiler, 1987;Arce et al, 1998;Henary and Russell, 2007;Kalmatsky, 2013 those developed for chemical engineering students, involves simple batch reaction rather than reaction within a continuous reactor with feed and exit flows. One reason for this limitation is the difficulty in measuring dye or bleach concentrations (and thus reaction extent) in flowing streams, or within agitated reactors that have continuous reactant entrance and product exit flow streams.…”

Nucleophilic Reactivities of Bleach Reagents

“…It is generally recognized that the hydroperoxide anion, hypochlorite, or persulfate are nucleophilic species that undergo analogous reactions with organic electrophiles. Although several of these reactions had been studied kinetically and reactions of bleach reagents with cationic organic food dyes are used in tutorials for introducing kinetic methods to students, a direct comparison of reactivities of different oxygen-transfer reagents is not available to date.…”

An introduction to digital microfluidic concepts in chemistry using a macroscopic droplet generator

“…After mixing with the bleach solution, the oxidation takes place and the mixture becomes colorless in a couple of minutes, as shown in Figure 1B. According to the literature 12 , the reaction kinetics writes as…”

“…To conduct this activity, we selected a simple redox reaction involving a food coloring molecule, Erythrosin B (commercially known as E127), and bleach (ClO -) as the oxidizing agent 12,13 . The reaction scheme is summarized in Figure 1A.…”